Underground map vital for subway project: Surjadi

Underground map vital for subway project: Surjadi

JAKARTA (JP): Governor Surjadi Soedirdja wants the
administration to develop an underground map of the capital
before subterranean development projects begin.

Once the planned subway project and underground shopping
centers are completed, Jakarta would have an underground city, he
said yesterday.

"So, underground mapping is badly needed by the city to
prepare the necessary regulations, to anticipate underground
developments and to prevent further conflicts in the future,"
Surjadi said after a meeting at City Hall.

Poor planning of underground projects could cause serious
problems because such areas will play an important role in the
future due to the scarcity of land on which to build, he said.

Other big cities overseas, such as Singapore, have already
developed below ground level, for mass rapid transportation
networks and shopping centers, he said.

"The efforts have been made due to the limited land available
on the surface," Surjadi said.

According to the head of the city's Mapping and Land
Measurement Agency, Mochammad Sidarta, underground mapping is an
important way to identify the geology of the land before
beginning construction.

"Based on underground mapping, the administration can
determine kind of projects should be allowed in which areas,"
Sidarta said.

He, therefore, urged the administration to complete the city's
underground mapping before starting the construction of the
proposed US$2.3 billion subway.

"With underground mapping, we'll find out whether the planned
routes for the subway project are possible to construct," Sidarta
said.

The project is scheduled to run from Blok M shopping area in
the south to Kota railway station in the north, passing streets
which are home to dozens of skyscrapers.

Deputy Governor of Economic and Development Affairs Tb.M. Rais
said Thursday that underground mapping could also be used to
preserve the city's groundwater and reduce the use of deep and
artesian wells.

"Uncontrolled use of artesian and deep wells could leave holes
in the ground which would eventually lead to salt water
intrusion."

He said that the administration had asked government
topographers to form a team to collect information and data to
determine which areas' artesian wells might soon run dry.

"The city should start controlling the use of groundwater to
protect the environment," Rais said.

Once the underground mapping completed, he said, the city was
also planning to conduct a sea map, starting with Jakarta bay.

Data from the city's mining agency shows that one third of the
city's groundwater, particularly in North Jakarta, is of the
poorest quality.

Areas in which water quality is particularly low include
Cilincing, Kapuk, Muara Karang, Sunter, Tanjung Priok, Kelapa
Gading -- all in North Jakarta; Gambir, Jatinegara, Karet,
Matraman, Petamburan, Senen, Tanah Abang -- in Central Jakarta,
and Pulogadung and Cakung in East Jakarta.

These areas need 250 injection wells, which could help
replenish groundwater, and 30,000 ground wells. (ste/07)